The field of the invention is camera cranes.
Camera cranes are often used in motion picture and television production. The motion picture or television camera is typically mounted on a crane arm supported on a mobile base, dolly, or truck. The mobile base may be pushed and steered by hand. Larger units, which have more weight carrying capacity, and longer reaches, typically have electric driving motors powered by onboard batteries. Some mobile bases also including conventional gasoline or diesel engines, may also serve as over the road vehicles.
Camera cranes generally have a crane arm supported on a base, with a camera platform at one end of the arm, and a counter weight at the other end. The crane arm can be pivoted by hand to raise and lower the camera, and also to pan to the left or right side. A leveling system is often included to maintain the camera platform in a level orientation, as the elevation angle of the arm changes. Some mobile bases may include a self leveling or an extendible center post or column, which the crane arm can be mounted on.
With the development of high definition digital television cameras, and remote controlled motion picture cameras, filming can be achieved without a camera operator behind the camera. Rather, the remotely-controlled camera may be suspended on a crane arm, with the camera operator monitoring the image captured by the camera via a remote monitor.
Due to the variety of filming or video locations, the camera crane arm should advantageously be portable and lightweight. On the other hand, the arm must be rigid enough, when assembled, to resist bending and sagging, and to avoid excessive whipping motion of the camera during crane arm movement. Most camera cranes are made up from modular segments or sections, and have a fixed length. The segments are joined together until an arm of desired length is formed. With these types of arms, the length can be changed only by adding or removing segments. This is a time consuming process, as segments and leveling arms are bolted into place or removed. In addition, each time the length of the arm is changed, the arm must be rebalanced, by adding or removing counter weights. More importantly, crane arms having a fixed length cannot achieve various camera movements.
As a result, telescoping camera cranes have been developed. These types of cranes have a telescoping arm that can extend and retract. This allows for a much broader range of camera movement. While existing telescoping camera cranes have had varying degrees of success, existing designs have several disadvantages. Generally, the telescoping camera cranes available now use various electrical systems. Consequently, these cranes tend to have performance problems if used in rain or wet conditions. Attempts to avoid or reduce these problems by wrapping or tenting the electrical components provide mixed results. Of course, these types of cranes also cannot be used underwater. In addition, these types of cranes tend to be very large, heavy, and bulky. This makes transportation and set up time consuming and difficult. As production time is usually extremely expensive, time saving features are highly significant.
Moreover, under certain conditions, these types of telescoping cranes can cause unintended or undesirable camera movements, due to bending, flexing, twisting, or vibration of the crane arm. Noise generated from moving parts in these types of cranes, when the arm is extended or retracted, can also disrupt filming or recording.
Accordingly, various engineering challenges remain in designing an improved camera crane.